It has been suggested in the past that different building block elements be made from plastic. For instance, a group of play-building blocks have been provided which consist mainly of a square building block body which is equipped on one side surface with one or more projections and which is provided on the opposing surface with one or more recesses which is conjugate to the projections. The projections of another building block element may then be pressed into these recesses by a small deformation into extended position or in a position offset by 20.degree.. By such an interlocking of a number of building blocks, area and volume structures may be formed. These known building elements, however, have the disadvantage that the fitting of several building elements can only be made to opposing surfaces which are equipped with a conjugate element, i.e., a projection or a recess. To a surface positioned at a right angle to the base surface, no other building block may be attached. Furthermore, it is not possible with these known building elements to connect these building elements by struts positioned at an acute angle, for example an angle of 45.degree..
Furthermore, it is known to provide a building block group made from plastic to make area- or volume-shaped designs, which group consists of a cubical building block basic element and one connecting element. The basic element contains at least two opposing surfaces and dove-tail shaped grooves which are pressed onto correspondingly-shaped connecting members to connect one building block element to the other. Also, there is a building block group available wherein the basic elements are already equipped with a dove-tail shaped protrusion in place of the dove-tail groove, so that they may be connected to another basic element without a connecting member, which element, however, has to have a dove-tail groove. Also with this group, the basic elements can only be placed in a certain predetermined position. By use of a 45.degree. element, it is possible to create an acute angle, but deviations from this angle are not possible. Based on the dove-tailed groove and the dove-tailed protrusion, an additional attaching of further basic elements is not possible on every location, but only on the end surfaces. It is, therefore, an outstanding object of the invention to provide a structural system capable of being used to construct a wide range of configurations.
Another object of this invention is the provision of structural elements of simple design which may be locked together to form strong structural combinations.
A further object of the present invention is the provision of structural elements for use in buildings or the like formed inexpensively of plastic.
It is another object of the instant invention to provide structural system consisting of elements which are simple in construction, inexpensive to manufacture, and which are capable of a long life of useful service with a minimum of maintenance.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.